Wavelength-chirality demultiplexer of nondiffracting Bessel surface plasmon polariton beam based on hexagonal star nanostructure

Nondiffracting Bessel surface plasmon polariton (SPP) beams have unique self-healing, nondivergence, and linear transmission properties, which can effectively suppress the diffraction of the beam and improve the capacity of resisting disturbance, exhibiting wide applications in plasmonic devices and on-chip interconnection circuits. Here, we propose a plasmonic device for the selective excitation of six-channel nondiffracting SPP beam utilizing both wavelength and chirality demultiplexing techniques. This device is capable of coupling and directing circularly polarized light with three different wavelengths and chirality into nondiffracting Bessel SPP beam with six different propagation paths, greatly enhancing the freedom of information transmission in the on-chip interconnect circuit. Meanwhile, the multi-channel selective excitation function of the device is experimentally verified by scanning near-field optical microscopy (SNOM). This work provides a new strategy for the development of demultiplex SPP devices and a great prospect for applications such as on-chip interconnect circuits.